From cec59c440a05c241846e8fe9d2575a2dafb56fd9 Mon Sep 17 00:00:00 2001 From: Jinliang Zheng Date: Tue, 15 Apr 2025 23:36:58 +0800 Subject: kernfs: switch global kernfs_idr_lock to per-fs lock The kernfs implementation has big lock granularity(kernfs_idr_lock) so every kernfs-based(e.g., sysfs, cgroup) fs are able to compete the lock. This patch switches the global kernfs_idr_lock to per-fs lock, which put the spinlock into kernfs_root. Signed-off-by: Jinliang Zheng Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20250415153659.14950-2-alexjlzheng@tencent.com Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/dir.c | 14 +++++++------- fs/kernfs/kernfs-internal.h | 1 + 2 files changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index fc70d72c3fe8..355d943ffe27 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -27,7 +27,6 @@ DEFINE_RWLOCK(kernfs_rename_lock); /* kn->parent and ->name */ */ static DEFINE_SPINLOCK(kernfs_pr_cont_lock); static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by pr_cont_lock */ -static DEFINE_SPINLOCK(kernfs_idr_lock); /* root->ino_idr */ #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) @@ -584,9 +583,9 @@ void kernfs_put(struct kernfs_node *kn) if (kernfs_type(kn) == KERNFS_LINK) kernfs_put(kn->symlink.target_kn); - spin_lock(&kernfs_idr_lock); + spin_lock(&root->kernfs_idr_lock); idr_remove(&root->ino_idr, (u32)kernfs_ino(kn)); - spin_unlock(&kernfs_idr_lock); + spin_unlock(&root->kernfs_idr_lock); call_rcu(&kn->rcu, kernfs_free_rcu); @@ -639,13 +638,13 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, goto err_out1; idr_preload(GFP_KERNEL); - spin_lock(&kernfs_idr_lock); + spin_lock(&root->kernfs_idr_lock); ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC); if (ret >= 0 && ret < root->last_id_lowbits) root->id_highbits++; id_highbits = root->id_highbits; root->last_id_lowbits = ret; - spin_unlock(&kernfs_idr_lock); + spin_unlock(&root->kernfs_idr_lock); idr_preload_end(); if (ret < 0) goto err_out2; @@ -681,9 +680,9 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, return kn; err_out3: - spin_lock(&kernfs_idr_lock); + spin_lock(&root->kernfs_idr_lock); idr_remove(&root->ino_idr, (u32)kernfs_ino(kn)); - spin_unlock(&kernfs_idr_lock); + spin_unlock(&root->kernfs_idr_lock); err_out2: kmem_cache_free(kernfs_node_cache, kn); err_out1: @@ -989,6 +988,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, return ERR_PTR(-ENOMEM); idr_init(&root->ino_idr); + spin_lock_init(&root->kernfs_idr_lock); init_rwsem(&root->kernfs_rwsem); init_rwsem(&root->kernfs_iattr_rwsem); init_rwsem(&root->kernfs_supers_rwsem); diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 40a2a9cd819d..24e9514565ac 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -40,6 +40,7 @@ struct kernfs_root { /* private fields, do not use outside kernfs proper */ struct idr ino_idr; + spinlock_t kernfs_idr_lock; /* root->ino_idr */ u32 last_id_lowbits; u32 id_highbits; struct kernfs_syscall_ops *syscall_ops; -- cgit v1.2.3